It's just a fuse. They basically come in two flavors: fast and slow blow at various current values. Decades ago, a popular surge protector that was sold at some local audio dealers(The Coax Max), which was not an audiophile product by design, claimed superior lightning protection, got me curious to find out what was inside one. The only unusual thing was that the fuse looked like white paper under the glass, which I later found was a fast-blow ceramic type. When I called the company and asked about it, they were rather mad that I opened it up, and while not fully telling me that this was the major reason for its ability to catch a lightning strike quicker than the normal types, that was the reason. I later started replacing many fuses with ceramic. There's no difference sonically, just better protection, although later some audio-types believed they did. A fuse cannot improve your CD Transport unless there is an issue with the fuse. I have heard the difference where a dirty fuse was creating an intermittent issue in an amplifier. The dealer removed the fuse, polished it squeaky clean and shiny along with the fuse holder, applied a couple of tiny drops of Tweek(remember that stuff?), and put it back, and the amp performed like a champ. I'm still not sure what you're after. Do you have a problem with its sound or think a different fuse will improve it?
Anyhoo, I'll add this tidbit to the breakdown of what those codemarkings mean.
.L: Denotes a low breaking capacity, meaning it is designed to interrupt a relatively low amount of short-circuit current. A high-capacity fuse would be marked with an 'H'.
